JP5837300B2 - Method and apparatus for scoring and separating brittle materials with a single radiation beam - Google Patents

Description

Cross-reference of related applications

  This application was filed on May 15, 2007, and is related to US patent application Ser. No. 11/803428, entitled “Method and Apparatus for Scoring and Separating a Brite Material with a Single Beam of Radiation”. Which is incorporated herein by reference.

  The present invention relates to a method and apparatus for separating fragile materials, and more particularly to a method for scoring and separating glass substrates using only a single radiation beam.

  Glass plates are conventionally cleaved or separated by mechanical means. By mechanical means, the glass is scored along a predetermined path (scored) and then the plates are separated by applying mechanical bending forces to one or both portions of the plate. During the scoring step, median (vent) cracks are formed that extend only to a portion of the overall thickness of the plate.

  Another conventional method forms an initial crack in the plate. And by directing a laser to the crack, glass is heated and a crack is extended | stretched along a predetermined path | route. Patent Document 1 by Kondrenenko describes a process in which a beam spot has a short elliptical shape and the longest axis of the spot is less than 20 mm. The reported scoring speed was low and varied between about 10 mm / sec to 120 mm / sec depending on the glass type. U.S. Pat. No. 6,057,038 to Allaire et al. Teaches a significantly longer elliptical spot with the longest axis exceeding 40 mm. U.S. Pat. No. 6,057,031 to Hoekstra et al. Discloses the use of multiple laser beams prior to the scoring beam to increase the scoring speed. U.S. Pat. No. 6,057,076 teaches a similar approach based on using several beams to increase the scoring speed.

  In the separation step, the opening crack is deepened by a bending moment applied to the opening crack as described above or by generating a tensile stress by heating the score line with a laser. For example, Patent Document 5 describes using a circular or elliptical second laser beam that travels behind a scoring beam.

US Pat. No. 5,692,284 US Pat. No. 5,776,220 US Pat. No. 6,211,488 US Pat. No. 6,800,831 US Pat. No. 6,541,730

  The techniques described above generally require several steps and / or laser beams to achieve both scoring and separation functions. Such multi-step, multi-beam methods add cost and complicate the optical implementation of the scoring and separation process. What is needed is a non-contact method of scoring and separating a brittle material (eg, a glass substrate) in a single step without adding the complexity of multiple beams from multiple radiation sources.

  The present invention allows scoring and separation of plates of brittle material in a single pass of the radiation beam and using only a single radiation source.

  According to an embodiment of the present invention, providing a plate of brittle material, forming an elongated radiant zone on the plate, and forming a cooling zone on the plate that intersects the radiant zone, Scoring and separating the plates by forming a scoring portion and a separation portion of the radiation zone and providing relative movement between the radiation zone and the cooling zone intersecting the plate. A method for separating a plate of brittle material is disclosed. Advantageously, scoring and separation is performed on the plate of brittle material with a single pass of the radiation zone and cooling zone on the surface of the brittle material, the radiation zone and cooling zone being constant during scoring and separation. It is preferable to have the following spatial relationship. The brittle material is preferably a glass plate or a substrate.

  In another embodiment, providing a plate of brittle material, forming an elongate radiation zone on the plate by irradiating the surface of the plate with an elongate laser beam, and a portion of the radiation zone on the plate. Forming a cooling zone that overlaps the plate, and scoring the plate and separating the plate by providing relative movement between the radiation zone and the cooling zone that partially overlap the plate of brittle material. A method for separating materials is described.

  In yet another embodiment, an apparatus for scoring and separating a brittle material deforms the laser source and the laser beam emitted by the laser source into an elongated beam, and converts the elongated beam into the brittle material. At least one optical system that directs onto the surface, thereby forming a single radiation zone on the material, and a nozzle that directs the coolant stream to impinge on the surface of the brittle material, the impinging coolant Provides relative movement of the nozzle, the radiating zone intersecting the brittle material and the impinging coolant intersecting the radiating zone to provide a leading and trailing portion of the radiating zone relative to the direction of movement of the radiating zone And a transfer device for scoring and separating the brittle material during a single pass of the radiant zone and impinging coolant.

  By practicing the present invention, by reducing the complexity of instruments required to separate brittle materials such as glass plates, and combining the scoring function with the separation function in a single pass of the scoring / separation beam By reducing the time required to separate the brittle material and providing accurate alignment with the separation function of the scoring function (ie alignment of the scoring part of the beam with the separation part of the beam) By improving the effectiveness of the scoring and separation process, and eliminating the need for mechanical scoring of the material and the inherent chipping that occurs, the quality of the edges of the separated material can be improved.

  Embodiments of the present invention may be used off-line to individually break the plates of brittle material, or on-line as in the manufacturing process for making glass plates. For example, embodiments of the present invention can be introduced as part of a downdraw glass forming process, such as a fusion downdraw glass plate process, to remove (separate) individual glass plates from a moving glass ribbon. , Thereby replacing current mechanical scoring and breaking processes.

  Both the foregoing general description and the following detailed description are intended to present embodiments of the invention and provide an overview and framework for understanding the nature and features of the claimed invention. It should be understood that The accompanying drawings are included to provide a further understanding of the invention, and are incorporated in and constitute a part of this specification. The drawings illustrate exemplary embodiments of the invention and, together with the description, serve to explain the principles and operations of the invention.

1 is a schematic view of an apparatus for separating a glass plate or a glass substrate according to an embodiment of the present invention. FIG. 3 is a plan view of a “radiation zone” that a laser forms on a surface of a substrate when a laser beam emitted by the laser is incident on the surface of the glass substrate. FIG. 2 is an enlarged perspective view of a region of FIG. 1 where a laser beam is incident on the surface of a glass substrate. Fig. 4 shows an embodiment in which a jet of coolant overlaps with a part of the incident laser beam and the radiation zone is approximately bisected. FIG. 4 illustrates an embodiment in which a jet of coolant overlaps a portion of an incident laser beam and the beam leading edge is shorter than the trailing edge. FIG. 3 shows a cross-sectional view of a glass substrate showing how open cracks are only partially propagated in the glass substrate by the preceding part of the laser emission zone. FIG. 3 shows a cross-sectional view of a glass substrate showing how open cracks are propagated through the entire thickness of the glass by the subsequent part of the radiation zone. FIG. 6 is a plan view of another embodiment according to the present invention in which a single laser beam is masked to provide two elongate radiation zones separated by a cooling zone created by impinging coolant.

  In the following detailed description, for purposes of explanation and not limitation, example embodiments disclosing certain details are set forth in order to provide a thorough understanding of the present invention. However, it will be apparent to those skilled in the art having the benefit of this disclosure that the present invention may be practiced in other embodiments that depart from the specific details disclosed herein. Furthermore, descriptions of well-known devices, methods, and materials may be omitted so as not to obscure the description of the present invention. Finally, where applicable, like reference numerals refer to like elements.

  Referring to FIG. 1, an apparatus 10 for cleaving brittle material according to one embodiment of the present invention is shown. The brittle material can be, for example, a glass article, a ceramic article or a glass ceramic article. For the purpose of further explanation, a glass substrate and in particular a glass plate suitable for use in the manufacture of liquid crystal displays will be assumed and described below. However, it should be noted that the present invention is applicable to scoring and separation of other products.

  The apparatus 10 includes a light delivery system 12 that irradiates a glass substrate (glass plate) with radiation, a coolant nozzle 16, a coolant source 18, and associated piping 20 necessary to transport the coolant to the nozzle 16. And a cooling fluid discharge system. The light delivery system 12 includes a radiation source 22, a circular polarizer 24, a beam expander 26 and a beam shaping system 28.

The light delivery system 12 may further include optical elements that redirect the beam 32 of radiation from the radiation source 22, such as mirrors 34, 36 and 38. The radiation source 22 is preferably a laser that emits a laser beam having a wavelength and output suitable for heating the glass substrate at a position where the beam is incident on the glass substrate. In one embodiment, laser 22 is a CO ₂ laser operating at a wavelength of 10.6 μm and an output of 100 watts or greater.

The laser beam 32 emitted by the laser 22 is typically substantially circular in cross section (ie, the cross section of the beam perpendicular to the longitudinal axis of the beam). The light delivery system 12 is operable to deform the laser beam 32 to have a significantly elongated shape when the beam is incident on the glass substrate 14, thereby creating an elongated footprint or “radiation zone” on the substrate. "40 is provided. The boundary of the radiation zone is defined as the point where the beam intensity has been reduced to 1 / e ² of its peak value. Beam 32 passes through circular polarizer 24 and is then expanded by passing through beam expander 26. The expanded laser beam then passes through a beam shaping system 28 to form a beam that provides an elongated radiation zone 40 at the surface of the substrate. The beam shaping system 28 may comprise, for example, one or more cylindrical lenses. However, it should be understood that any optical element capable of shaping the beam emitted by the laser 22 to provide an elongated radiation zone on the substrate 14 may be used. FIG. 2 shows a schematic diagram of the radiation zone 40. The major axis of the radiant zone 40 is preferably substantially longer than the minor axis 44. In some embodiments, for example, the major axis 42 is at least about 10 times as long as the minor axis 44. In some preferred embodiments, the major axis 42 of the radiating zone 40 is at least about 100 mm in length, but may be at least about 200 mm or even longer than 300 mm, and the minor axis 44 is typically less than about 2 mm. , About 1.5 mm or less, or even 1 mm. However, the length and width of the radiation zone 40 depends on the desired scoring / separation speed (beam translation speed), glass plate thickness, laser power, etc., and the length and width of the radiation zone can be changed as needed. May be.

  As best shown in FIG. 3, the coolant nozzle 16 discharges a jet 46 of cooling fluid onto the surface 47 of the glass substrate 14. In some embodiments, the nozzle 16 emits a substantially parallel coolant jet having an inner diameter of approximately several hundred micrometers (eg, 200 μm to 300 μm) and a diameter of typically about 300 μm to 400 μm on the surface of the glass. . However, as with the radiant zone 40, the diameter of the nozzle 16 and the substantial diameter of the coolant jet 46 may be varied as needed for specific process conditions. In some embodiments, it is preferred that the area of the glass substrate (cooling zone) directly impacted by the coolant is shorter in diameter than the short axis of the radiation zone. However, in other embodiments, the diameter of the cooling zone may be larger than the minor axis of the emission zone 40 based on process conditions such as speed, glass thickness, laser power, and the like. Actually, the (cross-sectional) shape of the coolant jet may be other than circular, for example, the cooling zone may be fan-shaped so that a line is formed on the surface of the glass plate instead of a circular spot. The linear cooling zone may be oriented perpendicular to the long axis of the radiation zone 40, for example. Other shapes may be beneficial.

  The coolant jet 46 preferably includes water, but may be any suitable cooling fluid that does not foul or break the surface 47 of the glass substrate. In accordance with the present invention, the cooling fluid jet 46 is ejected onto the surface of the glass substrate 14, thereby forming a cooling zone 52 that intersects or overlaps the radiation zone 40, which is divided into two parts. That is, it effectively separates into a leading portion 48 in front of the cooling zone and a trailing portion 50 behind the cooling zone. Here, both the preceding part and the following part are for the direction of travel of the beam indicated by the arrow 54, and the preceding part and the following part are separated by the cooling zone 52. The term “front of the cooling zone” means the front of the broken line that touches the left side of the cooling zone 52 as shown by the arrow attached to the broken line in FIGS. 4A and 4B. Similarly, “behind the cooling zone” refers to the rear or right side of the broken line in contact with the right side of the cooling zone 52 as shown by the arrow attached to the broken line in FIGS. 4A and 4B. The cooling zone 52 may overlap the radiant zone 40 at or near the center point of the radiant zone, as shown in FIG. 4A, or as required to optimize the scoring and / or separation process, or FIG. 4B. As shown in FIG. 4, the radiation zone 40 may be closer to the other end than the one end.

  In order to scoring and separating the substrate 14, the apparatus 10 may further comprise means for providing relative movement between the glass substrate 14 and the beam 32 incident on the substrate (ie, the radiation zone 40). This can be achieved by moving the substrate 14 relative to the beam 32 or by moving the beam 32 (and thus the radiation zone 40) relative to the substrate. For large substrates, such as those having dimensions corresponding to the area of the substrate 47 exceeding several square meters, beam movement may be preferred. This is especially true for very large sheets. For example, substrates used in the manufacture of optical displays can have a thickness of less than 1 mm, often less than about 0.7 mm, and can exceed 10 square meters. It may not be practical to move such a large sheet of very thin glass. If it is not practical to move the plate, the light delivery system 12 may be attached to a suitable stage, such as an xy linear stage or a gantry system, thereby traversing the beam 32 and coolant 46 across the glass substrate 14. Can do. It should be noted that the radiant zone 40 and the cooling zone 52 move simultaneously so that their relationship remains substantially constant. If the light delivery system 12 is too large, even this approach may not be practical. Alternatively, during the scoring and separation process, many of the optical components and the glass substrate 14 may be held stationary and the laser beam 32 may be directed to a “flying head”, which is the laser beam Translates with respect to and substantially parallel to the glass substrate 14 such that 32 is directed onto the glass substrate 14. For example, the floating head 56 may include a beam shaping system 28 and a mirror 38. In this case, only the floating head need be moved to change the direction of the beam and to traverse the beam across the substrate. Methods for moving only the plate or light delivery system 12 or floating head 56 are well known in the art and will not be described further.

  The radiation zone 40 heats the glass substrate 14 as it traverses across the surface 47 of the substrate 14. The radiant zone 40 is effectively separated into two parts 48 and 50 by impinging a coolant jet 46 on the surface 47 across the radiant zone 40 to provide a partially overlapping cooling zone 52. . As shown in FIG. 4A, when the radiant zone 40 crosses in the direction indicated by the arrow 54, the leading portion 48 of the radiating zone 40 performs the scoring function and the trailing portion 50 of the radiating zone 40 performs the separation function. As the leading portion 48 of the radiant zone 40 traverses the substrate along the scoring path 59 (FIG. 3), the substrate is heated. The coolant jet 46 rapidly cools the heated portion of the substrate (via the cooling zone 52), i.e., rapidly cools, so that the substrate entrance surface 47 (surface upon which the laser beam 32 is incident), as shown in FIG. 5A. Opening cracks 60 extending to a partial depth in the main body of the glass plate 14 are formed. That is, the open crack 60 only partially traverses the thickness of the substrate. Then, the subsequent portion 50 of the radiant zone that immediately follows the preceding portion of the radiant zone reheats the quench portion of the substrate, and the open crack extends through the entire thickness of the substrate, as shown in FIG. Are separated along line 59 (FIG. 3).

  The separation speed (eg, the crossing speed of the beam on the surface of the substrate) can be controlled, for example, by changing the position of the point 52 where the coolant jet 46 is incident on the substrate 14 with respect to the radiation zone 40. . For example, the cooling zone 52 is positioned closer to or farther from any particular end of the radiating zone 40 to optimize scoring and / or separation (ie, positioned off center). can do.

  In another embodiment shown in FIG. 6 according to the present invention, a portion of the laser beam 32 may be masked, thereby forming two collinear elongated radiation zones 64, 66 from a single beam. By collinear means that the long (longest) axis of each radiation zone is on a single line. The masking of the beam 32 can be accomplished, for example, by placing an appropriately shaped obstacle (mask (not shown)) in the path of the beam 32. The coolant jet 46 can then be directed onto the glass substrate 14 to provide a cooling zone 52 in the masked portion 68 of the beam 32 between the radiating zones 64, 66. Similar to the previous embodiment, using the arrangement of the mask area and the subsequent arrangement of the cooling zone 52 in the mask portion, the thermal gradient provided by the beam and coolant and the depth of the initial scoring opening crack that follows. Can be controlled. As in the previous embodiment, the beam 32 and the coolant jet 46 move simultaneously so that relative movement between the radiation zone (s) and the cooling zone does not occur.

  It should be emphasized that the above-described embodiments of the invention, in particular any "preferred" embodiment, are merely possible examples of embodiments shown for a clear understanding of the principles of the invention. . There may be many variations and modifications to the above-described embodiments of the invention without departing substantially from the spirit and principles of the invention. All such modifications and variations are intended to be included herein within the scope of this disclosure and the present invention and protected by the following claims.

Claims (10)

A method for separating brittle materials,
Providing a plate of brittle material;
Forming an elongated radiation zone on the plate;
Forming a cooling zone on the plate that intersects the radiation zone to form a scoring portion comprising a preceding portion and a cooling zone and a separation portion comprising a subsequent portion in the radiation zone;
Scoring the plate and separating the plate by providing relative movement between the plate and the intersecting radiation and cooling zones;
Applying the scoring and separating the plates comprises:
(1) The plate is heated through a leading portion of the radiation zone, the heated portion of the plate is rapidly cooled through a cooling zone, and an open crack extending to a partial thickness of the plate is formed. ,
(2) Reheating the quenched portion through the subsequent portion of the radiation zone and extending the open crack throughout the thickness of the plate, without any manipulation after the reheating, A method characterized in that it completely separates the plates of brittle material.   The method of claim 1, wherein the step of forming an elongated emission zone comprises irradiating the plate with a laser beam.   The method of claim 1, wherein the scoring portion and the separation portion have different lengths.   The method of claim 1, wherein the step of forming a cooling zone comprises impinging a cooling fluid on the plate.   The method according to claim 1, wherein the brittle material is glass or glass ceramic.   The method of claim 1, wherein the scoring portion and the separation portion are equal in length. An apparatus for scoring a brittle material and separating the brittle material,
A laser source;
At least one optical system that transforms a laser beam emitted by the laser source into an elongated beam, directing the elongated beam onto the surface of the brittle material, thereby forming a radiation zone on the material When,
A nozzle that directs a coolant stream to impinge on the surface of the brittle material, the impinging coolant being between the leading and trailing portions of the radiation zone relative to the direction of movement of the radiation zone A nozzle intersecting the radiation zone;
Scoring the brittle material during one pass of the radiant zone and the impinging coolant by providing relative movement between the brittle material and the intersecting radiant zone and the impinging coolant, and the brittle material Separating the transfer device;
Comprising
The transfer device is
(1) The plate is heated through a leading portion of the radiation zone, the heated portion of the plate is rapidly cooled through a cooling zone, and an open crack extending to a partial thickness of the plate is formed. ,
(2) Reheating the quenched portion through the subsequent portion of the radiation zone and extending the open crack throughout the thickness of the plate, without any manipulation after the reheating, An apparatus configured to completely separate the plates of brittle material.   8. A device according to claim 7, characterized in that the coolant impinges on a central point of the radiation zone.   8. A device according to claim 7, characterized in that the coolant impinges closer to the other end than to one end of the radiation zone.   The apparatus according to claim 7, further comprising a mask for masking a part of the laser beam.

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